Heat the oil and add the onions. Saute on medium heat until nicely browned.
Add the ginger and garlic and stir for a minute.
Add the tomato and stir for another minute.
Add the collard greens, salt, red chilli powder and water.
When it comes to a boil, cover with a tight-fitting lid, turn the heat to low, and allow the veggies to simmer away for 1 1/2 to 2 hours.
If there is still water remaining at the bottom of the pan, turn the heat to medium or high and let it evaporate.
Serve hot as a side dish with rice and dal or with rotis.